Steam-actuated ejector



1%he, 192a 11,444,539

R. N. EHRHART STEAM. ACTUATED EJECTOR Original Filed Sept. 21, 1917 INVENTOR.

- I Z 7 agmcmolm6fi anif HIS ATTORNEYSIN FACT Patented Feb. 6, 1923.

RAYMOND N. EHRHART, OF JEANNETTE,

HOUSE ELECTRIC 8:. MANUFACTURING 00., A

PENNSYLVANIA, ASSIGNOR TO WESTING- GORPOEA'I'ION OF PENNSYLVANIA.

STEAM-ACTUATED EJECTOR.

Application filed September 21, 1917, Serial No. 192,503.

To (all whom 2'25 may concern Be it known that I, RAYMOND N. EHRHART, a citizen of the United State, and a resident of Jeannette, in the county of Allegheny and State of Pennsylvania, have made a new and useful Invention in Steam-Actuated Ejectors, of which the following is a specification.

This invention relates to steam actuated eject-01's and has for an object to produce an ejector capable of being employed as an air ejector for condensers or other apparatus in which a high vacuum is to be maintained.

A further object is to produce an ejector which is more effective and has a greater air handling capacity per unit of weight and space occupied than other ejcctors now in use and known to me.

A further object is to produce an improved fluid actuated air ejector which is simpler in details of construction and is simpler to manufacture than similar ejectors now in use and known to me.

These and other objects are attained by means of an ejector embodying the features herein described and illustrated.

In the drawings: Fig. l is a diagrammatic view of a well known form of steam actuated air ejector.

Fig. 2 is a diagrammatic sectional view of a diffuser forming a part of an ejector similar to that illustrated in Fig. 1.

Fig. 3 is a diagrammatic View of a number of diffusers which, in aggregate, have the same'capacity and the same compression ratio as the diffuser of Fig. 2.

Fig. 4 is a diagrammatic sectional View of an ejector embodying my invention.

Figs. 5, 6 and 7 are transverse sections through the diffuser 16 taken respectively on the lines 5-5, 66 and 7-7 of Fig. 4.

Steam actuated ejectors capable of withdrawing air from steam condensers or containers in which a high vacuum is maintained, must be so designed that the various fluid passages. are properly proportioned with relation to each other in order toprovide an ejector which is capable of starting and is capable of maintaining the desired vacuum with sufficient economy to be commercially practical.

Leblanc Patents Nos. 1,175,461 and 1,215,- 321 of March 14-, 1916 and February 6, 1917 respectively set forth ejectors capable for use as air pumps for steam condensers and disclose in part the difficulties encountered Renewed July 22, 1922. Serial No. 576,870. by ordinary ejectors and overcome by the Leblanc ejector inventions.

My present invention has for its object to produce an air ejector capable of accomplishing the results attained by the Leblanc ejector, but which is more compact and. consequently better adapted for commercial use where ejectors of relatively large capacity are necessary.

In Fig. 1, I have diagrammatically illustrated a Leblanc ejector for the purpose of comparing it with the ejector or" the same or greater capacity, illustrated in Fig. 1 as an embodiment of my invention. The ejector of Fig. 1 includes a ring of nozzles 8, capable of discharging motive fluid into and through a diffuser 7, which communicates directly with an air inlet port 6. The outlet of the difiuser 7 discharges into a second convergent divergent diffuser 9, the discharge of which communicates with the atmosphere. A series of nozzles 11 discharges into and through the diffuser 9. The nozzles 8 converge so that the stream of steam discharged from them conforms more or less closely to the contour of the converging portion of the diffuser 7. The nozzles 11 are similarly inclined so that the steam issuing from them moves in a path which is substantially parallel to the adj acent walls of the tube 9. In order to obtain an efficient and at the same time an effective ejector, it is necessary to proportion the throat areas of the diffusers to the outlet areas in such a way that the desired pres sure conversion is accomplished in each diffuser. Inasmuch as the angle of divergence of the diffusers must be carefully determined in order to accomplish the desired result and therefore must be more or less constant in diffusers designed to accomplish the same degree of compression, it will be apparent that ejectors designed to pass large volumes of steam and air will of necessity be relatively long and that the increase in length will necessitate an increase in thiclc ness of material and consequently the amount of material used. IVhen it is considered that the ejector should be operated in a vertical position, it will be apparent that for large sizes the ejector is not only ungainly and expensive 011 account of size, but will necessitate a relatively large amount of head room. The question of head room alone is an item where the ejector is eminto and through the annular diffuser.

ployed as a part of a marine installation and consequently a reduction in length is often as important as a reduction in weight.

In Fig. 2, I have illustrated a difluser which has, for example, a 6 angle from the smallest portion or throat to the largest portion or outlet.

In Fig. 3, I have illustrated four smaller diffusers having in total the same throat area and outlet area as the diffuser of Fig. 2 and each having the same angle of di vergence. It will, therefore, be apparent that if the four diffusers of Fig. 3 are grouped together their length will be much less than that of the diffuser of Fig. 1, whereas they will be capable of accomplishing the same results as could be accomplished by the diffuser of Fig. 2.

In Fig. l, I have embodied this idea in an ejector, but instead of employing separate diffusers of reduced cross section, I have replaced the relatively long diffusers of the Leblanc ejector by relatively short annular diffusers 14 and 16 having passages 14L and 16'. The diffuser 14: may be considered as having the same throat area and outlet area as the diffuser 7 and its angle of divergence may also be considered as that of the diffuser 7 The same comparison may be made between the diffuser 16 and the diffuser 9. Another advantage gained by the arrangement of diffusers illustrated in Fig. l is that the motive fluid delivery nozzles, cooperating with the diffusers, may extend axially of the ejector and in this way simplify the operation of machining the entire ejector. In addition to this, the series of nozzles 8 of the Leblanc ejector may be well replaced by one annular nozzle 17, which is axially aligned with the annular diffuser 1a and so arranged as to. discharge the stream of steam issuing from it axially with relation to the annular passage through the diffuser. The same is true of the means for delivering motive fluid to the second diffuser 16, and in the drawings I have illustrated a single annularnozzle 20 axially arranged with relation tothe annular diffuser 16 and so located as to deliver an annular stream of motive fluid As illustrated, the nozzle 17 receives motive fluid from a steam chest 18, and the nozzle 20 receives motive fluid from an annular steam chest 22, so arranged as to provide a minimum amount of resistanceto the fluid issuing from the diffuser I l and entering the diffuser 16. Both nozzles 17 and 20 are divergent nozzles, each being designed to expand the motive fluid traversing it to substantially the pressure normally existing at the outlet end of the nozzle.

The air intake to the ejector is illustrated at 15 and the atmospheric exhaust port is shown at 21. It will, of course, be apparout that the annular nozzle 17 may be replaced by a group of nozzles arranged in an annular series, or by nozzles of different angles and arranged in different rows. The same is true of the nozzle 20, although I prefer to employ a single annular nozzle for delivering steam to the second diffuser tube.

In Fig. 5, I have illustrated the arrangement of the webs 24c employed for holding the central wall 24: of the annular diffuser 16 in place. A similar arrangement of webs may be employed in connection with the diffuser 14L and if necessary the steam chamber 22 may be supported by webs. Figs. 6 and 7 illustrate respectively the annular nozzle 20 and the annular diffuser 16.

While I have illustrated and described but one embodiment of my invention, it will be apparent to those skilled in the art that various changes, modifications, additions and omissions may be made in the apparatus illustrated without departing from the spirit and scope of the invention, as setforth b the appended claims.

What I claim'is:

1. In combination in a. steam actuated air ejecting device, a diffuser communicating with a source of fluid to be ejected, a motive fluid delivery nozzle for discharging a stream of motive fluid into and through said diffuser, an annular diffuser arranged substantially in the same direction asthe first mentioned diffuser and coml'nunicating with the outlet of the latter, and annular divergent nozzle structure for expanding and delivering motive fluid into and through said annular diffuser.

2. In a steam operated air ejector, substantially annular convergent-divergent diffuser communicating with a. receptacle to be evacuated, divergent annular nozzle structure for expanding motive fluid and for delivering it into said diffuser, a second diffuser communicating with the outlet of the first diffuser, and annulardivergent nozzle structure located between said diffusers for expanding motive fluid and for delivering the fluid so expanded into the second diffuser.

3. An air ejector comprising the combination of a first substantially annular convergent-divergent diffuser, annularly arranged divergent nozzle structure for discharging motive fluid into the diffuser, a second substantially annular convergent-divergent diffuser communicating with thefirst diffuser, and annularly arranged. divergent nozzle structure arranged between the diffusers and adapted to discharge motive fluid into the second diffuser.

4. An air ejector comprising a substantially annular convergent-divergent diffuser adapted to communicate air to be withdrawn and substantially anwith asource of i the converging nular divergent nozzle structure adapted to discharge motive fluid into the diffuser, the axes of the diffuser and nozzle structure extending in the same direction and in the direction of flow of motive fluid and air.

An air ejector comprising a convergent-divergent difluser constructed with cross-sections of the fluid passage therethrough each defining a substantially annular area, in combination with divergent fluid expanding nozzle structure which corresponds in shape and position with said diffuser so as to effectively deliver actuating fluid therethrough.

6. In a fluid translating device, the com bination of a substantially annular diffuser and divergent expansion nozzle structure for expanding and discharging motive fluid at high velocity intothe annular diffuser, the axes of the nozzle and the diffuser extending in the same direction and in the direction of flow of motive fluid.

7. A fluid translating device comprising a longitudinally extending annular convergent-divergent diffuser, an inlet chamber communicating with the converging portion of the difiuser, and annular divergent expansion nozzle structure having its axis substantially coincident with the axis of the diffuser for discharging motive fluid through at least a part of the inlet chamber and into portion of the diffuser.

8. In a two-stage ejector, the combination of a longitudinally extending annular convergent-divergent diffuser adapted to communicate with a source of air to be withdrawn, annularly arranged divergent nozzle structure for discharging motive fluid through the diffuser, a second longitudinally extending annular convergent-divergent diffuser in communication with the first diffuser, and a second annularly arranged clivergcnt nozzle structure arranged between the diffusers and adapted to discharge motive fluid through the second diffuser.

9. In an ejector, the combination of an annular convergent-divergent diffuser adapted to communicate with a source of air to be withdrawn, annularly arranged divergent nozzle structure adapted to expansively discharge motive fluid at high velocity through the diffuser, a convergent-divergent diffuser in communication with the first diffuser, and divergent nozzle structure adapted to expansively discharge motive fluid at high velocity through the second diffuser, the axes of the first and second nozzle structures and the diffusers extending in the same direction and in the direction of flow of motive fluid and air.

10. In an ejector, the combination of a substantially annular convergent-divergent diffuser adapted to communicate with a source of medium to be withdrawn, substantially annularly arranged divergent nozzle structure adapted to expansively discharge motive fluid at high velocity through the diffuser, a second substantially annular convergent-divergent diffuser in communication with the first diffuser, a substantially annular motive fluid chest arranged between the diffusers, substantially annular divergent nozzle structure in communication with the chest and adapted to expansively discharge motive fluid therefrom at high Velocity through the second diffuser, the discharge from the first diffuser adapted to flow through and about the chest and the nozzle communicating therewith.

In testimony whereof, I have hereunto subscribed my name this 20th day of September, 1917 RAYMOND N. EHRHART.

Witness C. W. MGGHEE. 

